Partition Map Schemes: HFS+ and FAT32 partitions with OSX and Windows

Question

OK so I know this question has been practically beaten to death, but I keep finding conflicting information. I am using a 2011 MacBook Pro, on which I will set up Windows through Boot Camp. I recently purchased a 750 GB WD external hard drive to use with time machine for a backup on my Mac. However, I also need to be able to use part of this for Windows files. SO.. I intend to use the HFS+ partition for the the Mac (500GB) and create a FAT 32 partition (250GB) to use for backing up windows files (using it for solely computer modeling and need to be able to transfer/share files with Mac users who use Parallels as well as copying to PC desktops). My question is what to use as the partition map scheme. I have heard that when using these two partition types, a Master Boot Record is needed (so Windows can recognize the FAT32 partition) and also that a GUID partition map is required for use with time machine, meaning windows would no longer be able to read the FAT32 partition. Is there a way to reconcile this? Either using Time Machine with HFS+ partition that is set to MBR or uisng FAT32 on Windows with a GUID partition map? Also if I were to use Parallels (with a GUID setup) instead of Boot Camp, could that be the way to save the windows files to the FAT32 Partition and avoid problems with Time Machine not working with MBR? Thanks for any expertise, as I have heard that both setups that I have mentioned both will work and both will not work. Any experience with a similar situation?

Answer 1

Wow. Thanks for the extremely quick responses. Just for a few points of clarification.. I'm a complete newb at backing up strategies.
Steve, you would recommend to not backup files from my Mac OSX and files from Windows (also on my Mac) on the same drive, correct?
I appreciate the strategy of using it only as a backup, that makes quite a bit of sense. However, if I want to only backup my OSX files, and also store (solely as backup copies) say, a number of computer models (Rhino, Revit, etc.) that were created in Windows programs (not needing to store the entire Windows disk), would it not make sense to store these on the same drive in a different partition, creating the need for two different partition formats? And if I were to do this, maybe I should use NTFS instead of FAT32 (and reformat to GUID since that seems to be a standard for Apple and Windows 7 recognizes it..?) to keep them completely separate since the computer model files cannot be opened unless running the Windows programs.
How do you use your drive with HFS+ and NTFS if not for backups? I will not need to access the HFS+ backup files in Windows, nor need to access files from an NTFS partition in OSX, so that seems to simplify things in that, at least at the moment, I will not need any Paragon software.
Currently my drive is partitioned as HFS+ and FAT32 as MBR, with the HFS+ partition set up with Time Machine. It appears to be successful, I see my files in Mac HD -> "users" and all my docs, desktop items, etc. are listed. Seems that there is in fact no limit on TM's use of MBR maps, or else it is way above 160GB.
Third, are you using CarbonCopyClone in place of Time Machine or in addition to it? If in addition would it create the bit-wise clone on the same HFS+ partition as TM is backing up to? Or a separate drive? I'd like to only have one external that I am backing up to for simplicity's sake. I've never used TM before, so this is all new to me. Also, I suppose I have been missing the distinction between storing copies of files, and making a complete backup of a disk image... just now realizing the difference. Thanks so much.